Aerosol generating preparations



United States Patent 3,042,580 AEROSQL GENERATING PREPARATIONS Ernst Jacobi and Hans Brenner, Darmstadt, Germany,

assignors to E. Merck Aktiengesellschaft, Darmstadt,

Germany, a German corporation No Drawing. Filed Jan. 26, 1959, Ser. No. 788,718

Claims priority, application Germany Jan; 30, 1958 6 Claims. (Cl. 16739) The known self-smoldering preparations for fumigating, fogging or generating smokes or mists contain generally a combustible substance, such as, woodflour, lactose, etc., together with an oxygen-releasing agent, for instance, a nitrate, chromate, perchlorate, etc. and the substances to be fumigated, and when ignited at one point smolder throughout more or less rapidly, whereby the substances to be dispersed are vaporized or volatized in the smoldering zone. Such customarily known preparanons have the disadvantage that the substances to be dispersed which are heat sensitive or difiicult to volatize are mostly decomposed in the smoldering zone which reaches a temperature of several hundred degrees centigrade. In vlew of this situation, it is customary to distribute such sens1-' tive substances in form of an aerosol by means of special devices. This entails a substantial expenditure of apparatus, compressed gas, or similar means.

It is the object of the present invention to provide an aerosol generating preparation by means of which even thermally easily decomposable, and/or difiicult to volatize substances can be distributed in form of an aerosol without substantial material losses. According to the invention, aerosols can be produced by a thermal decomposition reaction of 1,5-eudomethylene-3,7-dinitroso- 1,3,5,7-tetraaza-cyclooctane.

It has been found that aerosol generating preparations which contain l,5-endomethylene-3,7 dinitroso-1,3,5,7- tetraazacyclooctane of the formula:

are suitable to eflectuate the distribution even of decomposable substances in aerosol form Within the space to be fumigated. The preparations are of the self-smoldering type so that no apparatus or other devices are required.

1,5 endomethylene 3,7 dinitroso 1,3,5,7 tetraaza-cyclooctane decomposes when it is ignited or acidified with evolution of heat and gas; The compound is not hygroscopic, and is readily available (see Mayer, Berichte der Deutschen Chemischen Gesellscha-ft, vol. 21, page 2888 (1888)). The compound is defined in this publication as dinitroso-pentamethylenetetramine, and burns with a bright flame after being ignited. When mixed with noncombustible and/or flame-retarding additives, or when locally heated to atleast 200 C. (in an acidic medium also possibly at temperatures below 200 C.) without use of a flame, a flame does not form at all, or if it flames, the flame can be readily snuffed out; and the decomposition reaction progresses correspondingly slower through the entire mass. Hence, 1,5-endomethylene- 3,7-dinitroso-1,3,5,7-tetraazacyclooctane permits the preparation of mixtures which, when locally ignited or heated, react progressively through the mass, whereby within the reaction zone the temperature is temporarily elevated and a large volume of gas is evolved. The peak temperature can be lowered to substantially below 200 C. by including a suitable proportion'of known non-combustible or inert fillers. Hence, the temperature is far below that of the red glow which isdbtained in the smoldering zone of the known smoke or mist generators. In addition to the low temperature, the substance to be released or volatized is further protected by moving it very quickly away from the heated reaction zone in the evolving gas.

g It has been further found that the quality of the aerosol generating preparations according to the invention, and the progress of the fumigating reaction, is improved by the addition of thermally decomposable nitrogen compounds, such as ammonium salts and/or cyanamide and/or urea or the salts thereof, and/or compounds which contain, as a structural element, the group:

the aerosol generating preparations in accordance with this invention. Since these substances are furthermore thermally decomposed, and while undergoing such decomposition, increase the pH factor in the reaction zone and also release an additional volume of gas, the pH- dependent decomposition reaction of the 1,5-endomethylene 3,7 dinitroso 1,3,5,7 tetraaza cyclooctane can be regulated and the formation of a flame can be sup pressed. Finally, these substances reduce the odor of formaldehyde which occurs when 1,5-endomethylene- 3,7-dinitroso-1,3,5,7-tetraaza-cyclooctane decomposes.

It was further found that a content of meltable, diflicultly combustible or non-combustible halogen compounds which split off hydrogen halides above C., such' as tetrachlorocyclohexanone, hexachlorocyclohexane, polyvinylchloride, tetrachlorophthalic acid anhydride, magnesium bromide, etc., lowers the pH factor in the reaction zone, and in the aerosol, and suppresses flaming without causing a deterioration of the storage properties of the aerosol generating preparations according to the invention.

Obviously, it is possible to add to these aerosol generating preparations the usual additives, such as fillers, salts, binding agents, resins (the latter also to regulate the rate of smoldering), means for regulating the moisture content, such as silicones or sorbitol, further scenting agents, dyes, denaturants,etc. One can also add further energy sources, as for example, Ba(NO lactose,

etc.

When sensitive substances are to be dispensed in form of an aerosol, fillersare particularly important since they allowa dilution of the mixture, thereby slowing the fumigation reaction. Depending upon the heat conductivity of the fillers, the zone from which the substances to be dispersed are expelled can be broadened or narrowed. For theuse in the aerosol generating preparations of this invention absorptive fillers have been found to be particularly advantageous when the substances to be dispersed in form of an aerosol are sensitive. Such fillers absorb the readily melting among those substances so that they do not melt away in the vicinity of the reaction zone, provided they are not substances which are already liquid at room temperature. Fillers of this kind are powdered silicic acid types and other silicates and oxides, particularly those which come under the heading colorless reinforcing fillers, furthermore alumina gel, finely discrete clays, diatomaceous earth, other metal oxides and also wood flour, cellulose powder, carbon black, graphite, finely powderized synthetic plastics, such as, polyvinyl alcohol and hardened aminoplasts, etc.

The' aerosol generating preparations according to the invention can be applied in any desired form, for instance, as powder, granules, tablets, small sticks, or as layers applied to a carrier, etc. The generation of the aerosol can be readily initiated by means of a match flame, a hot wire, a heating plate, a fuse cord or paper fuse. It is suflicient to ignite the aerosol generating preparations at one point. The reaction progresses from there throughout the mass.

The aerosol generating preparations according to the invention do not require apparatus, but they may, for instance, be fed continuously to a source of heat if they are sufficiently loose. The aerosol may also be propelled in a desired direction by means of a gas current, for instance, produced by a blower; or the production of the aerosol can be effected in a combustion chamber which has a small aperture from which the aerosol flows in the desired direction. It is also possible to apply additionally a strong electrostatic charge to the aerosol particles by means of suitable apparatus.

There are numerous fields of application for the aerosol generating preparations according to the invention, as for instance, those of pest control, plant protection, disinfection, for fireworks, for signalling purposes etc. The method can be used in any case where solid or liquid substances are to be dispersed in air or in other gases.

The following are examples in accordance with this invention:

Example I A powder constisting of 28 parts of 1,5-endomethylene- 3,7-dinitroso-1,3,5,7-tetraaza-cyclooctane and 72 parts of y-hexachlorocyclohexane is ignited at one point with a match. It reacts throughout without flame and expels a dense 'y-hexachlorocyclohexane aerosol.

Example 2 A powder which contains:

Parts 1,5 endomethylene 3,7 dinitroso-l,3,5,7-tetraazacyclooctane 30 Dicyandiamide 20 a-Hexachlorocyclohexane 20 Kieselguhr 12 Talc Aminoazobenzene-azo-fi-naphthol (Sudan red) 8 is touched at one point with a glowing or smoldering piece of paper impregnated with KNO It reacts throughout without flame and expels an intensely red-colored smoke.

is dipped at one corner into an aqueous slurry of 40 parts of dextrine, 7 parts of borax, parts of cellulose powder, 1 part of antimony pentasulfide, 12 parts of potassium persulfate and 25 parts of potassium bromate. This combustible composition is dried. A tablet ignited at its combustible portion-with a match reacts fiameless throughout, starting from there, and expels a dense smoke containing N-methylcarbamic acid phenylester.

' Example 4 A tablet weighing 4.1 grams and consisting of:

G. 1,5 endomethylene 3,7 dinitroso-1,3,5,7-tetraazacyclooctane 0.80 Dicyandiamide 0.45 P'olyvinylchloride 0.25

' 4 a-Hexachlorocyclohexane 0.95 Silicic acid 0.40 Swellable clay 0.80 Talc 0.17 N-methyl-carbamic acid-phenylester 0.65 'y-Hexachlorocyclohexane 0.35

reacts throughout when ignited at one corner with a match, and when the flame has been extinguished without further formation of flame and expels a dense smoke which contains the two last mentioned active ingredients.

Example 5 A powder consisting of:

Parts 1,5 endomethylene 3,7 dinitroso-1,3,5,7-tetraazacyclooctane 15 Dicyandiamide 30 Flowers of sulfur 30 N-trichloromethylthiotetrahydrophthalimide 25 is ignited as described in Example 2. It reacts throughout without forming flames. From the smoke which does not contain sulfur dioxide and which is Well tolerated by plants, a deposit and/or coating is formed, and even if the smoke is strongly diluted, this coating prevents the germination of mold spores.

Example 6 A powder consisting of:

Parts 1,5 endomethylene 3,7 dinitroso 1,3,5,7 tetraaza-cyclooctane 30 Dicyandiamide 30 Attapulgus clay (a highly absorptive clay) 25 N-diethyl-n-caprylic acid amide 15 is ignited as described in Examples 2 and 5. The mist contains the last mentioned active ingredient and repels insects.

Example 7 A powder which contains:

Parts 1,5 endomethylene 3,7 dinitroso 1,3,5,7 tetraaza-cyclooctane 30 Dicyandiamide 20 Aluminium hydroxide gel 10 2,2 dihydroxy 3,5,6 -.3',5',6' hexachlorodiphenylmethane 40 yields, in accordance with Examples 2, 5 and 6, a smoke which contains the last mentioned active ingredient.

reacts throughout without forming flames when ignited with a match and expels a smoke which contains 'y-hexachlorocyclohexane.

Example 9 A powder consisting of:

Parts 1,5 endomethylene 3,7 dinitroso 1,3,5,7 tetraaza-cyclooc-tane 44 Guanidine carbonate 15 Magnesium bromide 20 Parts Alumina gel 'y-Hexachlorocyclohexane Methylcarbamic acid-phenylester 6 reacts according to Example 1.

The content of l,5-endomethylene-3,7-dinitroso-1,3,5, 7-tetraaza-cyclooctane in the aerosol generating preparations according to the invention has been found to be most advantageous within the range from 5 to 55%. Fillers or diluents are usually used up to a content of in some casesit may be increased to It will be understood that the foregoing description of the invention and the examples set forth are merely illustrative of the principles thereof. Accordingly, the appended claims are to be construed as defining the invention Within the full spirit and scope thereof.

We claim:

1. A composition for use in the preparation of aerosols consisting essentially of l,5-endomethylene-3,7-di-nitroso- 1,3,5 ,7-tetraaza-cyclooctane in a concentration of approximately 5 to and a member of the group consisting References Cited in the file of this patent UNITED STATES PATENTS 2,637,678 Peer May 5, 1953 2,666,751 Wunderly Jan. 19, 1954 2,678,927 Wright et al May 18, 1954 2,707,695 Courtier May 3, 1955 2,754,276 Walker et al July 10, 1956 

1. A COMPOSITION FOR USE IN THE PREPARATION OF AEROSOLS CONSISTING ESSENTIALLY OF 1,5-ENDOMETHYLENE-3,7-DI-NITROSO1,3,5,7-TETRAAZA-CYCLOOCTANE IN A CONCENTRATION OF APPROXIMATELY 5 TO 55% AND A MEMBER OF THE GROUP CONSISTING OF INSECTICIDES, FUNGICIDES, BACTERICIDES, REPELLENTS, AND ORGANIC DYESTUFFS. 